Adjustable wrench

Abstract: An adjustable wrench has a handle and a head formed integrally at the anterior end of the handle. The head is provided with a fitting hole, a receiving hole, and a through hole in communication with the fitting hole. Located at two opposite sides of the fitting hole are two fixed clamping surfaces. A rotation knob is disposed in the receiving hole. An adjustment bolt is put through the through hole and the ring hole of the rotation knob such that one end of the adjustment bolt is received in the fitting hole. The one end of the adjustment bolt is provided with a movable clamping surface forming a clamping space in conjunction with the two fixed clamping surfaces. The ring hole of the rotation knob is provided with threads engageable with threads of the adjustment bolt. A location pin is fastened to the head such that the locating pin is inserted into a groove extending axially in the adjustment bolt. When the rotation knob is turned, the adjustment bolt is caused to move linearly to adjust the position of the movable clamping surface.

Description: FIELD OF THE INVENTION The present invention relates to an adjustable wrench. BACKGROUND OF THE INVENTION The conventional adjustable wrench is generally provided with a fixed jaw and a movable jaw, which form together a clamping mouth for fastening or loosening a fastener such as a hexagonal nut or bolt head. Such a prior art adjustable wrench as described above is defective in design in that it often fails to hold a nut or bolt head firmly at the time when the nut or the bolt head is twisted strenuously, and that the movable jaw is vulnerable to cracking. In US-A-4787275, there is disclosed an adjustable double-ended box wrench, including a wrench body defining large and small box wrenches, an adjustable jaw assembly including an elongated adjusting member and a rotatable adjuster that moves jaw end surfaces to adjust the sizes of the wrenches, and a cover plate that is secured to the wrench body to retain the adjustable jaw assembly. Each of the large and small box wrenches includes a pair of associated diverging portions and a pair of converging portions as well as an associated connecting portion that connect the associated engagement portions. Each of the connecting portions preferably has a connecting wall with curved ends that are tangential to associated engagement surfaces in order to prevent stress concentration during use. In one embodiment of the wrench, the rotatable adjuster is an adjusting nut that receives an externally threaded portion of the associated adjusting member to provide the adjustment. In another embodiment of the wrench, the rotatable adjuster is an adjusting screw that receives an internally threaded portion of the associated adjusting member to provide the adjustment. SUMMARY OF THE INVENTION It is the primary objective of the present invention to provide an improved adjustable wrench with means to facilitate the adjustment of the dimension of its clamping hole to fit hexagonal nuts or bolt heads of various dimensions. It is another objective of the present invention to provide an improved adjustable wrench with three symmetrical clamping surfaces for holding firmly a hexagonal nut or bolt head intended to be tightened or loosened. According to the present invention, there is provided an adjustable wrench comprising: a handle; a head formed integrally at one end of the longitudinal axis of said handle and provided with an upper surface, a lower surface parallel to said upper surface, and a fastener receiving hole extending through said head from said upper surface to said lower surface, said fastener receiving hole having two fixed clamping surfaces perpendicular to said upper and lower surfaces and symmetrical about a plane of symmetry containing the longitudinal axis of the wrench, said two fixed clamping surfaces being contained in two imaginary planes which extend in a direction opposite to said handle and which meet at an angle of 60 degrees; and an adjustment bolt mounted in said head such that said adjustment bolt is prevented from rotation but is able to move linearly along an axis thereof, which axis is contained in said plane of symmetry, and such that a penetration end of said adjustment bolt protrudes into said fastener receiving hole, said penetration end being provided with a movable clamping surface perpendicular to said upper and lower surfaces of said head so that said movable clamping surface is contained in an imaginary plane which is perpendicular to said plane of symmetry and which intersects each of said imaginary planes containing said two fixed clamping surfaces at an angle of 60 degrees; said head being further provided with a rotation knob received in a knob receiving hole in the head, the rotation knob having an central bore through which the adjustment bolt extends, the central bore being provided with threads engaging with threads on the adjustment bolt, thereby enabling the adjustment bolt to be axially moved by turning the rotation knob. characterised in that: said penetration end of said adjustment bolt has a flat end surface which is perpendicular to the axis of said adjustment bolt and is provided with an arresting block fastened thereto, said arresting block having an end surface coplanar with said flat end surface of said penetration end of said adjustment bolt for cooperating with said flat end surface to form said movable clamping surface; said fastener receiving hole is provided with a recess which is dimensioned to receive therein said arresting block and which is located in the end of said fastener receiving hole nearest to said handle; and said adjustment bolt is provided with a groove extending in the direction of the axis of said adjustment bolt and retaining therein one end of a locating pin fastened to said head such that said one end thereof is inserted into said groove so as to permit said adjustment bolt to move only linearly and axially when said rotation knob is turned. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a perspective view of a preferred embodiment of the present invention. FIG. 2 shows a sectional view of a portion taken along the line 2-2 as shown in FIG. 1. FIG. 3 shows a sectional view of a portion taken along the line 3-3 as shown in FIG. 1. FIG. 4 shows a top plan view of the preferred embodiment of the present invention. FIG. 5 is a top plan view of the preferred embodiment in use under a first condition, according to the present invention. FIG. 6 shows a top plan view of the preferred embodiment in use under a second condition, according to the present invention. DETAILED DESCRIPTION OF THE INVENTION Referring to FIGS. 1-6, an adjustable wrench 10 embodied in the present invention is shown to comprise a handle 12 and a rectangular head 14 formed integrally at one end of the longitudinal axis of the handle 12. Located at another end of the longitudinal axis of the handle 12 is a hang hole 16. The head 14 has an upper surface 18 and a lower surface 20, which are parallel to each other. The distance between the upper and the lower surfaces 18 and 20 is greater than the thickness of the handle 12. The longitudinal axis of the handle 12 has one end that is connected with one end of the longitudinal axis of the head 14 so as to form a shoulder 22 at the junction between the handle 12 and the head 14. In this preferred embodiment of the present invention, the handle 12 is slanted upwards at a predetermined angle, such as an angle of 15 degrees, from the junction between the handle 12 and the head 14 for facilitating the wrenching operation. The head 14 is provided with a fastener receiving hole 24 for receiving a hexagonal nut or bolt head, the receiving hole 24 having two fixed clamping surfaces 26 and 28 which are opposite in location to each other and are located at one end farther from the handle 12. These two fixed clamping surfaces 26 and 28 are located on opposite sides of the longitudinal axis X-X' of the head 14 such that the two fixed clamping surfaces 26 and 28 are equidistant from the axis X-X'. The two imaginary planes, as shown by the dotted lines in FIG. 4, containing the two fixed clamping surfaces 26 and 28 meet at an angle of 60 degrees. In addition, a top surface 30 is provided perpendicular to the longitudinal axis X-X' of the head 14. The top surface 30 is respectively connected with one end of each of the two fixed clamping surfaces 26 and 28, with another end of each of the two fixed clamping surfaces 26 and 28 being connected respectively with two inner surfaces 32 and 34. The head 14 is provided with a through hole 36 which is located between the surface of the receiving hole 24 and the shoulder 22 and is parallel to or coaxial with the longitudinal axis X-X'. Located between the end of the receiving hole 24 near the handle 12 and the handle 12 is a receiving hole 38 in communication with the through hole 36. A rotation knob 40 is disposed in the receiving hole 38. An adjustment bolt 42 is disposed through the through hole 36 and the ring hole 44 of the rotation knob 40 such that one end of the adjustment bolt 42 is received in the receiving hole 24. The adjustment bolt 42 is provided therein axially with a groove 46. A locating pin 48 is fastened to a partition wall 50 located between the receiving hole 24 and the receiving hole 38, with the inner end of the locating pin 48 being received in the through hole 36 and being retained in the groove 46. The ring hole 44 of the rotation knob 40 is provided with threads engageable with threads of the adjustment bolt 42. When the rotation knob 40 is turned, the adjustment bolt 42 is caused to move linearly in the direction of the axis thereof. It is suggested that the dimension of the rotation knob 40 is such that the surface of the rotation knob 40 is higher than the upper surface 18 of the head 14 when the rotation knob 40 is disposed in the receiving hole 38. Such an arrangement of the rotation knob 40 as described above is intended to facilitate the turning of the rotation knob 40. The adjustment bolt 42 has a penetration end 54 located in the receiving hole 24 and provided with a flat end surface 56. An arresting block 58 has a through hole 60 in which the penetration end 54 is held. A surface 62 of the arresting block 58 is coplanar with the flat end surface 56. The surface 62 and the flat end surface 56 form a movable clamping surface 64 contained in an imaginary plane which meets the two imaginary planes containing the two fixed clamping surfaces 28 and 26 at an angle of 60 degrees, as shown by the dotted lines in FIG. 4. Therefore, the receiving hole 24 is composed of two fixed clamping surfaces 26 and 28, and the movable clamping surface 64, which are corresponding respectively in location to three noncontiguous sides of a hexagonal nut or bolt head and which form together a clamping space adjustable in dimension to accommodate a number of hexagonal nuts or bolt heads of various dimensions. The penetration end 54 of the arresting block 58 serves to enlarge the area of the movable clamping surface 64. In addition, the space of the fitting hole 24 is enlarged by a recess 66 located at the end adjacent to the handle 12 and dimensioned to accommodate therein the arresting block 58. When a hexagonal nut 70 or bolt head 80 is to be worked on with the adjustable wrench 10 of the present invention, as shown respectively in FIGS. 5 and 6, the receiving hole 24 is first fitted over the nut 70 or the bolt head 80 such that the fixed clamping surfaces 26 and 28 of the wrench 10 are respectively in contact with the opposite sides 72 and 74 of the nut 70 or with the oposite sides 82 and 84 of the bolt head 80. Thereafter, the rotation knob 40 is turned until such time when the movable clamping surface 64 of the adjustment bolt 42 of the wrench 10 is intimately in contact with a lower side 76 or 86 of the hexagonal nut 70 or bolt head 80. As a result, the nut 70 or the bolt head 80 can be turned in the direction of a wrenching movement of the handle 12. It is readily apparent that the adjustable wrench 10 of the present invention has inherent advantages over the prior art adjustable wrench. The adjustable wrench 10 of the present invention is provided with a rotation knob 40 which makes the job of adjusting the size of the clamping space relatively easy. In addition, the clamping space of the adjustable wrench 10 of the present invention is formed by three clamping surfaces which meet respectively at an angle of 60 degrees. As a result, a hexagonal nut or bolt head can be held securely in the clamping space of the adjustable wrench 10 of the present invention. Moreover, the torsion of a wrenching movement of the handle 12 of the adjustable wrench 10 of the present invention is equally exerted on the three clamping surfaces, which are therefore less vulnerable to a crack caused by a strenuous twist of the hexagonal nut or bolt head.

Claims: An adjustable wrench (10) comprising: a handle (12); a head (14) formed integrally at one end of the longitudinal axis of said handle (12) and provided with an upper surface (18), a lower surface (20) parallel to said upper surface (18), and a fastener receiving hole (24) extending through said head (14) from said upper surface (18) to said lower surface (20), said fastener receiving hole (24) having two fixed clamping surfaces (26, 28) perpendicular to said upper and lower surfaces (18, 20) and symmetrical about a plane of symmetry containing the longitudinal axis of the wrench (10), said two fixed clamping surfaces (26, 28) being contained in two imaginary planes which extend in a direction opposite to said handle (12) and which meet at an angle of 60 degrees; and an adjustment bolt (42) mounted in said head (14) such that said adjustment bolt (42) is prevented from rotation but is able to move linearly along an axis thereof, which axis is contained in said plane of symmetry, and such that a penetration end (54) of said adjustment bolt (42) protrudes into said fastener receiving hole (24), said penetration end (54) being provided with a movable clamping surface (64) perpendicular to said upper and lower surfaces (18, 20) of said head (14) so that said movable clamping surface (64) is contained in an imaginary plane which is perpendicular to said plane of symmetry and which intersects each of said imaginary planes containing said two fixed clamping surfaces (26, 28) at an angle of 60 degrees; said head (14) being further provided with a rotation knob (40) received in a knob receiving hole (38) in the head (14), the rotation knob (40) having an central bore (44) through which the adjustment bolt (42) extends, the central bore (44) being provided with threads engaging with threads on the adjustment bolt (42), thereby enabling the adjustment bolt (42) to be axially moved by turning the rotation knob (40). characterised in that: said penetration end (54) of said adjustment bolt (42) has a flat end surface (56) which is perpendicular to the axis of said adjustment bolt (42) and is provided with an arresting block (58) fastened thereto, said arresting block (58) having an end surface (62) coplanar with said flat end surface (56) of said penetration end (54) of said adjustment bolt (42) for cooperating with said flat end surface (56) to form said movable clamping surface (64); said fastener receiving hole (24) is provided with a recess (66) which is dimensioned to receive therein said arresting block (58) and which is located in the end of said fastener receiving hole (24) nearest to said handle (12); and said adjustment bolt (42) is provided with a groove (46) extending in the direction of the axis of said adjustment bolt (42) and retaining therein one end of a locating pin (48) fastened to said head (14) such that said one end thereof is inserted into said groove (46) so as to permit said adjustment bolt (42) to move only linearly and axially when said rotation knob (40) is turned. An adjustable wrench (10) as claimed in claim 1 wherein said handle (12) extends at a predetermined angle relative to said upper and lower surfaces (18, 20) of said head (14). An adjustable wrench (10) as claimed in claim 2 wherein said upper and lower surfaces (18, 20) of said head (14) are separated by a distance greater than the distance between an upper surface and a lower surface of said handle (12); wherein said handle (12) and said head (14) meet at a shoulder (22); and wherein said head (14) is provided with a through hole (36) which is located between said shoulder (22) and a surface of said fastener receiving hole (24) and is in communication with said knob receiving hole (38), with said adjustment bolt (42) being disposed in said through hole (36) such that said adjustment bolt (42) can be caused to move linearly in the direction of the axis of said through hole (42). An adjustable wrench (10) as claimed in claim 3 wherein said two fixed clamping surfaces (26, 28) are located respectively on opposite sides of said plane of symmetry such that said two fixed clamping surfaces (26, 28) are equidistant from said longitudinal axis; and wherein said axis of said through hole (36) is parallel to said longitudinal axis of said head (14).

Inventors: CHANG JONG-SHING, CHANG, JONG-SHING
Applicants: CHANG JONG SHING, CHANG, JONG-SHING
Application year: 1994
Main classification: B25B13
IPC codes: B25B13